\begin{tikzpicture}
    \tkzDefPoints{0/0/O}
    \tkzDefPoint(160:1.5){A}
    \tkzDefPoint(220:1.5){B}
    \tkzDefPoint(320:1.5){C}
    \tkzDefPoint(70:1.5){D}

    \tkzDrawCircle[thick](O,A)
    \tkzDrawPolygon(A,B,C,D)
    \tkzDrawSegments(A,C  B,D)
    \tkzLabelPoints[left](A,B)
    \tkzLabelPoints[right](C)
    \tkzLabelPoints[above](D)
\end{tikzpicture}

